Quinones are found throughout biological systems where they function as redox mediators. We have synthesized a series of transition metal complexes with quinone-functionalized ligands and are studying the electrochemistry of the quinone groups in both aqueous and nonaqueous media. Using conventional electrochemistry, such as cyclic voltammetry, and spectroelectrochemistry, we are trying to understand the factors that influence the reversibility of the quinone/ semiquinone radical anion couple. FAB-MS is essential for the characterization of both the organic ligands and their metal complexes.